This invention relates to a snowmobile provided with a torsion mechanism which prevents the vehicle body of the snowmobile from inclining excessively under a centrifugal force when the snowmobile is quickly turned.
Generally, a snowmobile comprises a vehicle body, a pair of laterally spaced steering skis attached to the lower front portion of the vehicle body, a suspension mechanism disposed under the vehicle body behind the steering skis, and an endless truck assembly or an endless belt assembly resiliently supporting the vehicle body on snow by means of the suspension mechanism. The width of the truck assembly is smaller than the distance between the laterally spaced steering skis.
While the snowmobile is running at a constant speed, both the skis and the lower portion of the endless truck assembly should be kept in contact with the snow ground. Otherwise, the snowmobile could not run stably. But, if the skis are put in contact with the snow ground when the snowmobile starts to move or is being accelerated, the friction between the skis and the snow ground is so large that a so-called quick start dash or a quick acceleration cannot be provided. For a quick start dash or a quick acceleration, the skis should be lifted off the snow ground. This may be attained if the supported portion of the suspension mechanism on the vehicle body more forwardly than that of a conventional snowmobile such that there increase overhanging areas of the suspension mechanism extending rearwardly from the supported portion, and when the snowmobile starts to move or is being accelerated, the weight of the vehicle body acts concentratedly on the overhanging areas.
However, if the overhanging areas of the suspension mechanism in any of the conventional snowmobiles increase in the above-mentioned manner, one lateral edge of the endless truck assembly which is outward of the center of rotation with respect to the vehicle body is exerted with a greater force than the other lateral edge every time the snowmobile is quickly turned. In this case, that portion of the overhanging areas which corresponds to the lateral edge of the truck exerted by a greater force sinks or downwardly flexes so excessively that the vehicle body inclines considerably toward said one lateral edge under a centrifugal force. Such inclination of the vehicle body obstructs an easy, quick maneuverability of the snowmobile. Thus, the suspension mechanism of the conventional snowmobile could not be provided with larger overhanging areas.